The number of users in cellular systems has significantly increased. Accordingly, systems of 5th Generation have been increasingly demanded. Shifting from 4th Generation to 5th Generation demands some breakthroughs (e.g., improvement of both spectral efficiency and energy efficiency, and advanced radio frequency domain processing).
In terms of improving spectral efficiency, a multiple access technology (MAT) is an important element. As multiple access technologies, interleave division multiple access (IDMA), filter bank multicarrier (FBM), non-orthogonal multiple access (NOMA), and the like have been under study. Particularly in an IDMA system, interleavers make it possible to distinguish between different users and effectively eliminate interference between the users. The design of interleavers is one of the most important elements in an IDMA system, and technologies for achieving an appropriate design of interleavers have been developed.
For example, Patent Literature 1 below discloses a technology of performing transmission power control together with selection of an interleave pattern in order to eliminate interference between the users more effectively.